Conversion apparatus, radiation detection apparatus, and radiation detection system

ABSTRACT

A conversion apparatus includes pixels including switching elements provided on an insulating substrate and conversion elements disposed over the switching elements and connected to the switching elements. Conductive lines are coupled to the pixels and have terminal elements for providing a connection to an external circuit. The terminal elements are disposed in a metal layer that is formed over the conversion elements. The conversion apparatus further includes a transparent conductive layer covering surfaces of the terminal elements, and a protective layer covering edges of the terminal elements and having openings.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/456,155, filed on Jul. 7, 2006, entitled “CONVERSIONAPPARATUS, RADIATION DETECTION APPARATUS, AND RADIATION DETECTIONSYSTEM”, the content of which is expressly incorporated by referenceherein in its entirety. This application also claims the benefit ofJapanese Application Nos. 2005-201603 filed Jul. 11, 2005 and2006-181890 filed Jun. 30, 2006, which are both hereby incorporated byreference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to photoelectric conversion substrates,photoelectric conversion apparatuses, radiation detection substrates,and radiation detection apparatuses for use in medical diagnosticimaging apparatuses, non-destructive inspection apparatuses, analysisapparatuses using radiation, and the like. In this specification,radiation includes electromagnetic waves like visible light, X-rays,α-rays, β-rays, γ-rays, etc.

2. Description of the Related Art

In general, conventional medical diagnostic imaging can be classifiedinto two types: general imaging for obtaining still images, such asX-ray images, and fluoroscopic imaging for obtaining dynamic images. Thetype of imaging and an imaging apparatus to be used are selected asnecessary.

In conventional general imaging, two methods described below are mainlyused. One of the two methods is a screen-film imaging (hereafterabbreviated as SF imaging) method in which imaging is performed by filmexposure, development, and fixing using a screen film obtained bycombining a fluorescent plate and a film. The other method is a computedradiography imaging (hereafter abbreviated as CR imaging) method inwhich a radiographic image is recorded on a photostimulable phosphorplate as a latent image. Optical information corresponding to the latentimage is output by scanning the photostimulable phosphor plate with alaser, and the output optical information is read out with a sensor.However, general imaging has a problem in that processes for obtainingthe radiographic image are complex. In addition, although it is possibleto convert the obtained radiographic image into digital data, theradiographic image is secondarily digitized in such a case and it takesa long time to obtain a digitized radiographic image.

In conventional fluoroscopic imaging, an image intensifier imaging(hereafter abbreviated as I.I. imaging) method using a fluorescentmaterial and an electron tube is mainly used. However, conventionalfluoroscopic imaging has a problem in that the size of the device islarge since the electron tube is used. In addition, since the electrontube is used, view area (detection area) is small and it is difficult toobtain an image of a large area. In addition, there is also a problemthat the resolution of the obtained image is low since the electron tubeis used.

Accordingly, sensor panels in which pixels including conversion elementsfor converting radiation or light from a fluorescent material intoelectric charges and switching elements are arranged on a substrate in atwo-dimensional matrix pattern have recently been attracting attention.In particular, flat panel detectors (hereafter abbreviated as FPD) inwhich pixels having conversion elements constructed of non-singlecrystal semiconductor, such as amorphous silicon (hereafter abbreviatedas a-Si), and thin-film transistors (hereafter abbreviated as TFT)constructed of non-single crystal semiconductor are arranged on aninsulating substrate in a two-dimensional matrix pattern have beenattracting attention.

In the FPD, radiation having image information is converted intoelectric charges by the conversion elements, and the thus obtainedelectric charges are read out by the switching elements, so thatelectrical signals based on the image information can be obtained.Accordingly, the image information can be obtained directly from the FPDas digital signal information, and the image data can be easily stored,processed, transmitted, etc. Therefore, application of the radiographicimage information can be increased. Although the characteristics, suchas sensitivity, of the FPD can vary depending on imaging conditions, itis confirmed that the level of the characteristics of the FPD is thesame as or higher than those of the SF imaging method and the CR imagingmethod. In addition, since the electrical signals representing the imageinformation can be obtained directly from the FPD, the time required forobtaining an image can be reduced compared to those in the SF imagingmethod and the CR imaging method.

As an example of a FPD, a PIN-FPD including a sensor panel in whichpixels including PIN photodiodes made of a-Si and TFTs are arranged in atwo-dimensional matrix pattern is known. The PIN-FPD has a laminatedstructure in which a layer forming the PIN photodiodes is laminated on alayer forming the TFTs on a substrate. In addition, a MIS-FPD includinga sensor panel in which pixels including MIS photosensors made of a-Siand TFTs are arranged in a two-dimensional matrix pattern is also known.The MIS-FPD has a planar structure in which the MIS photosensors areformed in the same layer as a layer forming the TFTs on a substrate. Inaddition, a MIS-FPD having a laminated structure in which a layerforming the MIS photosensors is laminated on a layer forming the TFTs ona substrate is also disclosed in, for example, U.S. Patent ApplicationPublication No. 2003/0226974.

As an example of a FPD, the above-mentioned FPD discussed in U.S. PatentApplication Publication No. 2003/0226974 will be explained below. Here,a structure in which pixels are arranged in a 3-by-3 matrix pattern willbe described for simplicity.

FIG. 6 is a schematic equivalent circuit diagram illustrating anequivalent circuit of the conventional FPD discussed in U.S. PatentApplication Publication No. 2003/0226974. FIG. 7 is a schematic planview of a single pixel included in the conventional FPD discussed inU.S. Patent Application Publication No. 2003/0226974. FIG. 8 is aschematic sectional view of FIG. 7 taken along line VIII-VIII.

Light emitted from a wavelength converter in accordance with radiationincident thereon is converted into signal electric charges at each of aplurality of photoelectric conversion elements to which a bias voltagefor photoelectric conversion is applied. A plurality of switchingelements perform a transmission operation in accordance with drivesignals applied to drive lines 103 by a drive circuit 107, and thesignal electric charges obtained by the photoelectric conversionelements 101 are read out in parallel by a signal-processing circuit 106via signal lines 104. The signal electric charges read out in parallelare converted into a serial signal by the signal-processing circuit 106,and the thus obtained serial signal is converted from analog to digitalby an analog-to-digital (A/D) converter 108 and is then output.Accordingly, an image signal for a single image corresponding to theincident radiation that represents image information can be obtained.

In the above-described radiation detection apparatus using the FPD, thedrive lines 103 are connected to the drive circuit 107 for applying thedrive signals to gate electrodes of the switching elements 102 arrangedin the row direction. In addition, the signal lines 104 are connected tothe signal-processing circuit 106 for processing the signal electriccharges generated by the photoelectric conversion elements 101 andtransmitted from source or drain electrodes of the switching elements102 arranged in the column direction. In addition, bias lines 105 areconnected to a bias power source 109 having a first voltage for causingthe photoelectric conversion elements 101 to perform photoelectricconversion and a second voltage for applying a bias for setting thephotoelectric conversion elements 101 to an initial state. Theelectrical connections between the lines and the external circuits areprovided by terminal elements provided on the lines at one end thereof.For example, terminal elements included in a radiation detectionapparatus using a FPD discussed in Japanese Patent Laid-Open No.2003-319270 will be described below.

A protective layer that covers the photoelectric conversion elements andthe switching elements is removed in the entire area outside the pixelarea so as to form a connection area (open area), and the terminalelements are connected to respective integrated circuits (ICs) in thecontact area.

As described in, for example, International Patent ApplicationPublication No. WO98/32179, in the radiation detection apparatus towhich the ICs are connected, each of the ICs on an insulating substrateis covered by a sealing member (not shown) and is protected from theoutside.

However, in the above-described radiation detection apparatus using theFPD, there is a possibility that corrosion of the terminal elements willoccur. More specifically, since the protective layer is removed in theentire connection area and the terminal elements are not covered, theterminal elements are easily contaminated by moisture and impurities inthe atmosphere. As discussed in International Patent ApplicationPublication No. WO98/32179, each of the terminal elements is covered bya sealing member. However, moisture and impurities from an interfacebetween the sealing member and the insulating substrate cannot beblocked sufficiently. Therefore, contamination by moisture andimpurities at side faces of each terminal element and an interfacebetween the terminal element and the insulating substrate cannot besuppressed sufficiently. In particular, in a radiation detectionapparatus used for medical inspections, there is a possibility thatrubbing alcohol, moisture, etc., will directly come into contact withthe radiation detection apparatus. Accordingly, countermeasures for sucha situation are demanded.

In addition, since the protective layer is removed in the entireconnection area and the terminal elements are not covered, if conductiveadhesive enters a gap between the adjacent terminal elements, there is apossibility that a short circuit will occur between the adjacentterminal elements. In such a case, a desired drive operation cannot beperformed and an image cannot be obtained. Thus, there is a risk thatreliability and manufacturing yield will be reduced.

SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to a conversionapparatus and a radiation detection apparatus that can reliably preventcontamination by moisture and impurities from side faces of eachterminal element and an interface between the terminal element and aninsulating substrate.

According to an embodiment of the present invention, a conversionapparatus includes pixels, terminal elements and conductive linescoupled between the pixels and the terminal elements. The pixels includeswitching elements coupled to conversion elements. The switchingelements are disposed over an insulating substrate and the conversionelements are disposed over the switching elements. The conversionapparatus further includes a transparent conductive layer coveringsurfaces of the terminal elements and a protective layer covering edgesof the terminal elements and having openings. The lines include biaslines disposed over the conversion elements and coupled to an externalpower source circuit for applying a bias voltage to the conversionelements. The terminal elements to provide connections to an externalcircuit are disposed in a metal layer that is formed over the conversionelements.

According to another embodiment of the present invention, a radiationdetection apparatus includes pixels having switching elements coupled toconversion elements, terminal elements to provide connections to anexternal circuit, and conductive lines coupled between the pixels andthe terminal elements. The lines include bias lines coupled between theconversion elements and an external power source circuit to apply a biasvoltage to the conversion elements. Terminal elements are disposed in alayer that is formed over a layer including the conversion elements. Theradiation detection apparatus further includes a wavelength converterdisposed over the conversion elements for converting incident radiationinto visible light.

According to the embodiments of the present invention, contamination bymoisture and impurities from side faces of each terminal element and theinterface between the terminal element and the insulating substrate canbe reliably prevented. In addition, the adjacent terminal elements canbe reliably insulated from each other. Therefore, reduction inreliability and manufacturing yield can be prevented.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles ofexemplary embodiments of the invention.

FIG. 1 is a schematic circuit diagram of a photoelectric conversionapparatus and a radiation detection apparatus according to a firstembodiment of the present invention.

FIG. 2 is a plan view in which a part of the photoelectric conversionapparatus and the radiation detection apparatus according to the firstembodiment of the present invention is enlarged.

FIG. 3 is a schematic sectional view of the photoelectric conversionapparatus and the radiation detection apparatus according to the firstembodiment.

FIG. 4 is a sectional view of a photoelectric conversion apparatus and aradiation detection apparatus according to an embodiment of the presentinvention.

FIG. 5 is a diagram illustrating a radiation detection system to whichthe radiation detection apparatus according to embodiments the presentinvention can be applied.

FIG. 6 is a schematic circuit diagram illustrating a conventionalphotoelectric conversion apparatus and radiation detection apparatus.

FIG. 7 is a schematic plan view illustrating a single pixel in theconventional photoelectric conversion apparatus and radiation detectionapparatus.

FIG. 8 is a sectional view illustrating the conventional photoelectricconversion apparatus and radiation detection apparatus shown in FIG. 7taken along line VIII-VIII.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described below withreference to the accompanying drawings.

First Exemplary Embodiment

A first exemplary embodiment of the present invention will be describedin detail below with reference to FIGS. 1 to 3. FIG. 1 a schematiccircuit diagram of a photoelectric conversion apparatus and a radiationdetection apparatus according to the first embodiment of the presentinvention. FIG. 2 is a plan view in which a peripheral region of thephotoelectric conversion apparatus and the radiation detection apparatusaccording to the first embodiment of the present invention is enlarged.FIG. 3 is a schematic cross-sectional view of FIG. 2 taken along lineIII-III. In FIGS. 1 to 3, components similar to those included in theconventional FPD shown in FIGS. 6 to 8 are denoted by the same referencenumerals and detailed explanations thereof are thus omitted.

Referring to FIGS. 1 to 3, the structure includes an insulatingsubstrate 100, photoelectric conversion elements 101 that function asconversion elements, switching elements 102, drive lines 103, signallines 104, and bias lines 105. The insulating substrate 100 can be aglass substrate, a quartz substrate, a plastic substrate, etc. Thephotoelectric conversion elements 101 are MIS photosensors made of a-Siand the switching elements 102 are TFTs made of a-Si. Each of thephotoelectric conversion elements 101 and the corresponding switchingelement 102 form a single pixel. The pixels are arranged in atwo-dimensional matrix pattern, and a pixel area P is providedaccordingly. A plurality of contact holes are arranged in a region C(shown in FIG. 2) outside the pixel area P. As for the region C, it ispreferred that the layers are arranged so that the total film thicknessmay decrease toward terminal elements (e.g., 123, 124, 125 in FIG. 2)from the pixel area P. By such structure, the defects of the linescoupled between the contact hole and the terminal element can bedecreased.

The drive lines 103 are connected to gate electrodes 110 (shown in FIG.4) of the switching elements 102 arranged in a row direction, and areformed of a first metal layer M1, which is the same layer as a layerforming the gate electrodes 110 of the switching elements 102. Thesignal lines 104 are connected to source or drain electrodes 114 (shownin FIG. 4) of the switching elements 102 arranged in a column direction,and are formed of a second metal layer M2, which is the same layer as alayer forming the source or drain electrodes 114 of the switchingelements 102. The bias lines 105 are connected to an upper electrodelayer 120 for applying a bias voltage to the photoelectric conversionelements 101. Thus, a sensor upper electrode is provided. The bias lines105 are formed of a fourth metal layer M4 made of metal, such as Al.

In the first embodiment of the present invention, drive-line leadingportions 103 a are connected to the drive lines 103 via contact holes126 in the region C outside the pixel area P. The drive-line leadingportions 103 a are provided with drive-line terminal elements 123 forproviding electrical connection to a drive circuit 107 (shown in FIG.6). The drive-line leading portions 103 a and the drive-line terminalelements 123 are formed of the fourth metal layer M4, which is the samelayer as the top metal layer that forms the bias lines 105 in the FPDhaving a laminated structure. Accordingly, only a protective layer 121is laminated on the drive-line leading portions 103 a. Therefore, aconnection area (open area) OP1 for providing electrical connection tothe drive circuit 107 can be easily formed. In addition, since thedrive-line leading portions 103 a and the drive-line terminal elements123 are formed of the fourth metal layer M4 together with the bias lines105, similar to the bias lines 105, the surfaces of the drive-lineleading portions 103 a and the drive-line terminal elements 123 arecovered by the upper electrode layer 120. Therefore, corrosion of thefourth metal layer M4 can be prevented at the drive-line terminalelements 123.

In addition, signal-line leading portions 104 a are connected to thesignal lines 104 via contact holes 127 in the region C outside the pixelarea P. The signal-line leading portions 104 a are provided withsignal-line terminal elements 124 for providing electric connection to asignal-processing circuit 106 (shown in FIG. 6). The signal-line leadingportions 104 a and the signal-line terminal elements 124 are formed ofthe fourth metal layer M4, which is the same layer as the top metallayer that forms the bias lines 105 in the FPD having the laminatedstructure. Accordingly, only the protective layer 121 is laminated onthe signal-line terminal elements 124. Therefore, a connection area(open area) OP2 for providing electrical connection to thesignal-processing circuit 106 can be easily formed. In addition, sincethe signal-line leading portions 104 a and the signal-line terminalelements 124 are formed of the fourth metal layer M4 together with thebias lines 105, similar to the bias lines 105, the surfaces of thesignal-line leading portions 104 a and the signal-line terminal elements124 are covered by the upper electrode layer 120. Therefore, corrosionof the fourth metal layer M4 can be prevented at the signal-lineterminal elements 124.

In addition, first bias-line leading portions 105 a are connected to thebias lines 105 via contact holes 128 in the region outside the pixelarea P. The first bias-line leading portions 105 a are formed of thefirst metal layer M1, which is the same layer as a bottom metal layerthat forms the drive lines 103 in the FPD having the laminatedstructure. In addition, the first bias-line leading portions 105 a arealso connected to a second bias-line leading portion 105 b via a contacthole 129. The second bias-line leading portion 105 b is provided with abias-line terminal element 125 for providing electrical connection to abias power source 109 (shown in FIG. 6). The second bias-line leadingportion 105 b and the bias-line terminal element 125 are formed of thefourth metal layer M4, which is the same layer as the top metal layerthat forms the bias lines 105 in the FPD having the laminated structure.Accordingly, only the protective layer 121 is laminated on the bias-lineterminal element 125. Therefore, a connection area (open area) OP3 forproviding electrical connection to the bias power source 109 can beeasily formed. In addition, since the second bias-line leading portion105 b and the bias-line terminal element 125 are formed of the fourthmetal layer M4 together with the bias lines 105, similar to the biaslines 105, the surfaces of the second bias-line leading portion 105 band the bias-line terminal element 125 are covered by the upperelectrode layer 120. Therefore, corrosion of the fourth metal layer M4can be prevented at the bias-line terminal element 125.

In the present embodiment, the terminal elements 123 to 125 are formedof the fourth metal layer M4, i.e., the top metal layer in the FPD,together with the bias lines 105. The terminal elements 123 to 125 canalso be formed of the first metal layer M1 or the second metal layer M2.However, the terminal elements 123 to 125 can be formed of the fourthmetal layer M4. After the first metal layer M1 forming the drive lines103 is provided, a first insulating layer 111, a first semiconductorlayer 112, a first impurity semiconductor layer 113, the second metallayer M2, an interlayer insulating layer 115, a third metal layer M3, asecond insulating layer 117, a second semiconductor layer 118, a secondimpurity semiconductor layer 119, the fourth metal layer M4, the upperelectrode layer 120, the protective layer 121, and a phosphor layer(wavelength converter) 122 which converting the radiation into a visiblelight are laminated on the first metal layer M1. Therefore, the firstmetal layer M1 can be damaged due to heating, etching, etc., performedduring the process of forming the above-mentioned layers. In addition,after the second metal layer M2 forming the signal lines 104 isprovided, the interlayer insulating layer 115, the third metal layer M3,the second insulating layer 117, the second semiconductor layer 118, thesecond impurity semiconductor layer 119, the fourth metal layer M4, theupper electrode layer 120, and the protective layer 121 are laminated onthe second metal layer M2. Therefore, the second metal layer M2 can bedamaged due to heating, etching, etc., performed during the process offorming the above-mentioned layers. In addition, as the metal layersbecome increasingly damaged, contamination by moisture and impurities inthe atmosphere and corrosion due to the contamination can more easilyoccur. For example, when the metal surfaces are oxidized in the heatingprocess, wettability of the surfaces is increased and the surfacescannot be easily dried. As a result, washing using chemical liquid orthe like may be insufficient, which can lead to corrosion. In addition,there is a problem that the electric resistance is increased due to thesurface oxidization of the metal layers in the heating process. Inaddition, surface damages of the metal layers due to etching and residueof etching material may also lead to corrosion. In the presentembodiment, only the protective layer 121 is provided on the fourthmetal layer M4 that forms the terminal elements 123 to 125. Therefore,the fourth metal layer M4 is damaged only during the process of formingthe protective layer 121 and the process of forming the connection areas(open areas) OP1 to OP3 for the terminal elements 123 to 125,respectively. As a result, the fourth metal layer M4 is less damagedcompared to the other metal layers M1 to M3. Therefore, the fourth metallayer M4 will have good surface condition and is less likely to beeffected by contamination by moisture and impurities in the atmosphereand corrosion due to the contamination.

Next, the cross-sectional structure of the terminal elements will beexplained below with reference to FIG. 3, where the signal-line terminalelement 124 and the bias-line terminal element 125 are illustrated asexamples of terminal elements. In one embodiment, the upper electrodelayer 120 is formed of a transparent conductive layer constructed ofalloy oxide, such as ITO. In FIG. 3, the upper electrode layer 120 isprovided so as to cover the top and side faces of the signal-lineterminal element 124 on the insulating substrate 100, and a signal-lineterminal 131 is disposed accordingly. Then, the protective layer 121 andthe connection area (open area) OP2 are disposed such that at least thecontact interface between the signal-line terminal 131 and theinsulating substrate 100 (edges of the signal-line terminal 131) iscovered. Similarly, the upper electrode layer 120 is disposed so as tocover the top and side faces of the bias-line terminal element 125 onthe insulating substrate 100, and a bias-line terminal 132 is disposedaccordingly. Then, the protective layer 121 and the connection area(open area) OP3 are disposed such that at least the contact interfacebetween the bias-line terminal 132 and the insulating substrate 100(edges of the bias-line terminal 132) is covered. Although not shown inFIG. 3, the upper electrode layer 120 is also disposed so as to coverthe top and side faces of each drive-line terminal element 123, and adrive-line terminal (not shown) is disposed accordingly. In addition,the protective layer 121 and the connection area (open area) OP1 aredisposed such that at least the contact interface between the drive-lineterminal and the insulating substrate 100 (edges of the drive-lineterminal) is covered. Due to the above-described structure,contamination by moisture and impurities from the side faces of theterminal elements 123 to 125 and interfaces between the insulatingsubstrate 100 and the terminals (drive-line terminals, signal-lineterminals 131, and bias-line terminals 132) can be reliably prevented.In the present embodiment, the terminal elements 123 to 125 are coveredby the upper electrode layer 120. However, the present invention is notlimited to this, and the protective layer 121 and the connection areasOP1 to OP3 may also be disposed such that side faces of the terminalelements 123 to 125 and the contact interfaces with respect to theinsulating substrate 100 are covered by the protective layer 121.However, when the upper electrode layer 120, which is, in oneembodiment, a transparent conductive layer constructed of alloy oxidethat has a higher moisture resistance than that of a metal material, isused to cover the terminal elements 123 to 125 constructed of metallayers, contamination by moisture and impurities in the atmosphere canbe more reliably prevented.

In addition, in the present embodiment, the protective layer 121 is notremoved in areas between the adjacent terminal elements but is disposedso as to cover the side faces of terminal elements and the contactinterfaces with respect to the insulating substrate 100. In FIG. 3, theprotective layer 121 is not removed in the area between the signal-lineterminal 131 and the bias-line terminal 132 but is disposed so as tocover the side faces of the terminals 131 and 132 and the contactinterfaces with respect to the insulating substrate 100. Thus, theprotective layer 121 is disposed so as to cover the areas between theadjacent terminal elements. According to such a structure, even whenconductive adhesive for providing connection to ICs having externalcircuits flows into the areas between the adjacent terminal elements,short circuit can be prevented. Therefore, the terminal elements can bereliably insulated from each other and reduction in reliability andmanufacturing yield can be prevented.

In the above-described structure, the protective layer 121 is providedso as to cover the contact interfaces between the insulating substrate100 and the terminals (edges of the drive-line terminals, thesignal-line terminals 131, and the bias-line terminals 132). However,the present invention is not limited to this, and the contact interfaces(edges) may also be covered with a protective layer that is providedseparately from the protective layer 121 to cover at least the lines orthe terminals (drive-line terminals, signal-line terminals 131, andbias-line terminals 132).

In the present embodiment, the MIS-FPD using MIS photosensors as thephotoelectric conversion elements 101 and having a laminated structureis described as an example. However, as shown in FIG. 4, an embodimentof the present invention may also be applied to a PIN-FPD using PINphotodiodes 134 as photoelectric conversion elements. In FIG. 4,reference numeral 133 denotes a third impurity semiconductor layer intowhich impurities of the conductivity that is different from that of asecond impurity semiconductor layer 119 are implanted. In the PINphotodiodes 134, the second impurity semiconductor layer 119 can be ann-type a-Si layer and the third impurity semiconductor layer 133 can bea P-type a-Si layer. In addition, in the present embodiment, gap-etchingTFTs are used as the switching elements 102. However, the presentinvention is not limited to this, and gap-stopper TFTs and planer TFTsused in poly-Si TFTs may also be used. Thus, various modifications canbe made within the scope of the present invention as long as thecombination of the switching elements 102 and the photoelectricconversion elements 101 is provided and at least three metal layers forthe drive lines 103, the signal lines 104, and the bias lines 105 areused. In addition, in the present embodiment, the signal lines 104 andthe source or drain electrodes 114 are formed of the second metal layerM2, and a sensor lower electrode 116 are formed of the third metal layerM3, which is different form the second metal layer M2. However, thepresent invention is not limited to this, and the signal lines 104, thesource or drain electrodes 114, and the sensor lower electrode (thirdmetal layer) 116 may be formed of the same metal layer. However, in sucha case, the signal lines 104 cannot be arranged so as to overlap thesensor lower electrode. In addition, the photoelectric conversionelements and the switching elements cannot be arranged completely on topof one another. Therefore, the opening rate of the FPD is reducedcompared to the case in which different metal layers are used. Inaddition, in the present embodiment, the FPD including the MISphotosensors 101 using the second semiconductor layer 118 made of a-Sior the PIN photodiodes as the conversion elements is described. However,the present invention is not limited to this, and FPDs includingconversion elements using semiconductor layers made of a-Se or CdTe anddirectly converting radiation into electric charges may also be used.

Second Exemplary Embodiment

FIG. 5 is a diagram showing an X-ray diagnosis system to which the FPDradiation detection apparatus according to an embodiment of the presentinvention is applied.

X-rays 6060 generated by an X-ray tube 6050 pass through a chest area6062 of a patient or subject 6061 and are incident on a radiationdetection apparatus 6040 having a scintillator (fluorescent material) inan upper region. The incident X-rays include information of the insideof the patient's body. The scintillator generates light in accordancewith the incident X-rays, and the generated light is subjected tophotoelectric conversion so that electrical information is obtained. Thethus obtained information is digitized and subjected to image processingby an image processor 6070 that functions as a signal processing unit,and is then displayed by a display 6080 that functions as a display unitin a control room.

In addition, the image processor 6070 can transmit the electricalsignals output from the image sensor 6040 to a remote location via atransmission processing unit, such as a telephone line 6090, so that theinformation can also be displayed on a display unit (display) 6081 at adifferent location, such as a doctor's room. In addition, the electricsignals output from the image sensor 6040 may also be stored in astoring unit, such as an optical disc, so that a doctor at a remotelocation can diagnose the information using the storing unit. Inaddition, the information can also be recorded on a film 6110 by a filmprocessor 6100 that functions as a recording unit.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications, equivalent structures and functions.

1. A method of manufacturing a conversion apparatus, the conversionapparatus including pixels having switching elements disposed over aninsulating substrate and conversion elements disposed over the switchingelements and coupled to the switching elements; and lines coupled to thepixels and having terminal elements to provide a connection to anexternal circuit, wherein the lines include bias lines disposed over theconversion elements and coupled to an external power source circuit forapplying a bias voltage to the conversion elements, the methodcomprising: forming a metal layer covering the conversion elements andforming the terminal elements outside the pixels by the metal layer;forming a transparent conductive layer covering surfaces of the terminalelements; and forming a protective layer covering edges of the terminalelements and having openings.
 2. The method of claim 1, wherein the biaslines are formed by the metal layer.
 3. The method of claim 1, whereinthe protective layer is formed on the transparent conductive layer andcovers edges of the transparent conductive layer.
 4. The method of claim1, wherein the protective layer covers the pixels.
 5. The method ofclaim 1, wherein the terminal elements are formed on the substrate andthe protective layer covers side faces of the terminal elements.
 6. Themethod of claim 1, wherein the terminal elements are formed on thesubstrate and the transparent conductive layer covers side faces of theterminal elements.
 7. The method of claim 1, wherein the protectivelayer is formed so as to cover at least opposing edges of adjacentterminal elements in areas between the adjacent terminal elements. 8.The method of claim 1, wherein forming the switching elements includesforming a gate electrode by a first metal layer and forming a sourceelectrode and a drain electrode by a second metal layer.
 9. A method ofmanufacturing a radiation detection apparatus, the radiation detectionapparatus including pixels having switching elements coupled toconversion elements; terminal elements to provide connections to anexternal circuit; conductive lines coupled between the pixels and theterminal elements, the lines including bias lines coupled between theconversion elements and an external power source circuit to apply a biasvoltage to the conversion elements; and a wavelength converter disposedover the conversion elements for converting incident radiation intovisible light, the method comprising: forming a layer covering theconversion elements and forming the terminal elements outside the pixelsby the layer.
 10. The method of claim 9, wherein the terminal elementsand the bias lines formed by the same metal layer.
 11. The method ofclaim 9, wherein the switching elements are disposed over an insulatingsubstrate; wherein the conversion elements are disposed over theswitching elements; and wherein the bias lines are disposed over theconversion elements.
 12. The method of claim 9, further comprising:forming a transparent conductive layer covering surfaces of the terminalelements; forming a protective layer disposed on the transparentconductive layer so as to cover at least opposing side faces of at leasttwo adjacent terminal elements.
 13. A method of manufacturing anapparatus, the apparatus including pixels having switching elementscoupled to conversion elements; terminal elements to provide aconnection to an external circuit; and conductive lines coupled betweenthe pixels and the terminal elements, the conductive lines includingbias lines coupled between the conversion elements and an external powersource circuit to apply a bias voltage to the conversion elements, themethod comprising: the terminal elements are formed by a layer that isformed over a layer including the conversion elements.
 14. The method ofclaim 13, wherein the terminal elements and the bias lines are formed bythe same metal layer.
 15. The method of claim 14, wherein the switchingelements are formed over an insulating substrate; wherein the conversionelements are formed over the switching elements; and wherein the biaslines are formed over the conversion elements.
 16. The method of claim15, further comprising: forming a transparent conductive layer coveringsurfaces of the terminal elements; and forming a protective layerdisposed on the transparent conductive layer so as to cover at leastopposing side faces of at least two adjacent terminal elements.